London Metal Exchange provides information relating to the LME's third largest traded contract. Settlement prices, opening stocks and the forward price curve for Zinc are available.
http://www.lme.co.uk/zinc.asp

Shanghai Futures Exchange

Provides information relating to metals futures trading in China
http://www.shfe.com.cn/Ehome/index.jsp

ILZSG

International Lead and Zinc Study Group provides a wide variety of lead and zinc statistics.
http://www.ilzsg.org/ilzsgframe.htm